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Lactotransferrin
Cartoon diagram of recombinant human lactoferrin. Based on PDB 1b0l.
Available structures: 1b0l, 1bka, 1cb6, 1dsn, 1eh3, 1fck, 1h43, 1h44, 1h45, 1hse, 1l5t, 1lcf, 1lct, 1lfg, 1lfh, 1lfi, 1lgb, 1n76, 1sqy, 1vfd, 1vfe, 1z6v, 1z6w, 2bjj
Identifiers
Symbols	LTF; GIG12; HLF2
External IDs	OMIM: 150210 MGI: 96837 HomoloGene: 1754
Gene ontology Molecular function: • serine-type endopeptidase activity • ferric iron binding • peptidase activity • metal ion binding Cellular component: • extracellular region • extracellular space Biological process: • ion transport • iron ion transport • cellular iron ion homeostasis • humoral immune response • defense response to bacterium
Orthologs
	Human	Mouse
Entrez	4057	17002
Ensembl	n/a	ENSMUSG00000032496
Uniprot	n/a	Q3TP24
Refseq	NM_002343 (mRNA) NP_002334 (protein)	NM_008522 (mRNA) NP_032548 (protein)
Location	n/a	Chr 9: 110.86 - 110.89 Mb
Pubmed search	[1]	[2]

Lactoferrin (LF), also known as lactotransferrin (LTF), is a globular multifunctional protein with antimicrobial activity (bacteriocide, fungicide) and is part of the innate defense, mainly at mucoses. Lactoferrin is found in milk and many mucosal secretions such as tears and saliva. Lactoferrin is also present in secondary granules of PMN and also is secreted by some acinar cells. Lactoferrin can be purified from milk or produced recombinantly. Human colostrum has the highest concentration, followed by human milk, then cow milk.

Structure

Lactoferrin belongs to the transferrin family proteins (TF, melanotransferrin, ovotransferin, etc.). Its molecular mass is 80,000 u (80 kDa). It generally contains two bound Fe⁺² ions. It contains 4 identical domains, with two surrounding each iron atom.

Function

Lactoferrin antimicrobial activity is due partly to its high affinity for Fe³⁺ (ferric state). LF proteolysis produces lactoferricin, kaliocin-1 small peptides with antimicrobial activity. The combination of iron and lactoferrin in mucosal secretions modulate the ability and aggregation of pathogenic bacteria, and inhibit both bacteria and viruses by binding to host cells/viral particles. This inhibits the ability of bacteria and viruses to attach to cell membranes. It is also an antifungal agent.

Lactoferrin receptors have been found on brush-border cells, PMN, monocytes, Mφ and activated lymphocytes.

Lactoferrin inhibits dendritic cell-mediated HIV-1 transmission by blocking gp120 to DC-SIGN , which is a critical protein that never changes regardless of strain.^[1]

Genetics

In humans, the lactoferrin gene (LTF) is located on chromosome 3; location: 3q21-q23.

References

Further reading

External links

• lactoferrinresearch.org
• InVitria - sells Lacromin, a holo-lactoferrin (iron saturated)
• Expasy Database, chemical structure
• LTF on the National Center for Biotechnology Information
• Thompson.net Supported information about lactoferrin.
• FDA Lactoferrin Considered Safe to Fight E. Coli.
• Ventria Bioscience - a source of non-animal breastmilk equivalent lactoferrin
• Agennix.com A biopharmaceutical company focused on developing protein-based drugs for cancer and diabetic ulcers.
• Pharming.com A biopharmaceutical company producing lactoferrin.

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• This page was last modified on 12 October 2008, at 09:18.

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